Steam generator



Dec. 25, 1945.

T. C. JOHNSON S TEAM GENERATOR Filed April. 20, 1944 5 Sheets-Sheet l Dec. 25, 1945. vT. c. JOHNSON 2,391,628

STEAM GENERATOR Filled April 20, 1944 5 Sheets-Sheet 2 uv\ Un..

Dec. 25, 1 945. T. c. JOHNSON STEAM GENERATOR Dec. :25, 1945. T. C, JOHNSON 2,391,628

STEAM GENERATOR Filed April 20,1944 5 Sheets-Sheet 5 y 7? c. ummm @M @www Patented Dec. 25, 1945 UNITED STATES yPATENT OFFICE vSTEAM GENERATOR Thad C. Johnson, Clinton, S. Application April 20, 1944, Serial No. 531,944

10 Claims.

My invention relates to steam generators, for heating, power or general uses.

An important object of the invention is to provide apparatus of the above mentioned character which will practically instantaneously Igenerate steam, under positive' control with respect to retort temperature, pressure and introduction of water.

A further object of the invention is to provide? apparatus of the above mentioned character having the maximum degree of safety in operation.

A further object of the invention is to provide a boiler of the instantaneous or flash type wherein the water is introduced into the header or retort only as required and then only when conditions are right for instantaneous steam generation and further only when the pressure within the apparatus is below a selected high danger point.

A further object of the invention is to provide apparatus of the above mentioned character having the maximum speed and economy in operation which results from heating a small mass of the furnace unit and only the small quantity of water which is instantaneously converted into -f steam.

A further object of the invention is to provide apparatus of the above mentioned character which is simple in construction, easy to control and iiexible in operation.

A further object of the invention is to provide apparatus of the above mentioned character which is in the form of a compact unit, allowing the same to be installed in a small space, thus eliminating the need for the usual basement for receiving the conventional heating plant.

Other objects and advantages of the invention will be apparent during the course of the following description.

In the accompanying drawings forming a part of this application and in which like numerals are employed to designate like parts throughout the same,

Figure 1 is a side elevation, partly diagrammatic, of apparatus embodying my invention,

Figure 2 is a vertical longitudinal section taken online 2 2 of Figure 3,

Figure 3 is a horizontal section taken on line 3 3 of Figure 2,

Figure e is a front end elevation of the boiler,

Figure 5 is a transverse vertical section taken online 5 5 of Figure 2,

Figure 6 is a side elevation of the high temperature b lb, and associated elements, the `parts being shown partly diagrammatically,

Figure 7 is a side elevation of the low temperature bulb, and associated elements, the parts being shown partly diagrammatically, and

Figure 8 is a side elevation of a high pressure opening switch, and associated elements, the parts being shown partly diagrammatically.

In the drawings, wherein for the purpose of illustration is shown a preferred embodiment of my invention, the numeral I0 designates a casing of the boiler, which may be formed of refractory material, such as re brick, and having an exterior covering II of heat insulating material. The casing is provided in its bottom with a transverse bridge I2 and in its front end has an o-pening I3. At its top and near its rear end, the casing has a smoke hood or coupling i4 `for the escape of products of combustion and this coupling I4 is connected with the usual stack pipe I5. The casing I0 is also provided with vertically inclined baffles IS, secured to its sides.

Extending centrally and longitudinally within the casing IU is a lower header I'I, which is preferably cylindrical. The header is horizontally arranged and the forward end of the header Il is covered by a head I8 and this forward end is supported in a recess I9, formed in the front end of the casing l0. The rear end of the casing l0 has an opening 28, and the header Il extends through this opening 2!! to the exterior of the casing. The rear end of the header Il is open and is connected with a coupling 2l, connected with a pipe 22, which discharges into a float trap 23. This float trap discharges into a pipe 2d. The numeral 25 designates an upper header,

. v `which is preferably cylindrical and extends centrally and longitudinally within the casing l5, above and spaced from the lower header I'I and preferably parallel with the lower header and in alignment therewith. The opposite ends of the upper header are closed-by heads 26. The baffles I6 are arranged upon opposite sides or the headers I I and 25 and are spaced therefrom, and cause the heated gases and products of combustion, traveling rearwardly within the casing, to pass in close proximity to the headers. The lower ends of the baiiles IS are arranged at an elevation above the top of the bridge I2, as shown. The lower header I'I has vertical tubes 21 connected with its top portion and these vertical tubes are connected with the bottom portionY of the upper header 25. The tubes 21 place the headers in communication with each other and these tubes are spaced longitudinally of the headers, as shown. A pipe 28 is connected with the upper header 25, preferably near its front end lthe bottom of the tank 42.

and this pipe extends through the top of the casing I0, and is connected with a pressure gage 29, and a branch pipe 30. Connected with the header 25, near its rear end, is a steam main or outlet pipe 3l, equipped with a pressure relief va1ve32.V

The steam main 3| may be connected with a steam supply pipe 33, extending to a vertical pipe 34.

36, which may be equipped with valves 31, are connected with radiators 38 to supply steam thereto and these radiators have outlet pipes 39, connected with a steam return pipe 40, which is connected with the vertical pipe 34. The Vertical pipe 34 is connected at its lower end with a pipe 4I, leading into a condenser tank 42, and connected with the top of a condenser coil 43, the lower end of which is connected with a vertical pipe 44, provided at its upper end with a downturned outlet 45, arranged above the water level within the tank 42. A cold water supply pipe 44 leads into the tank 4,2 and has its lower end 45 discharging into the tank near its bottom. The pipeV 44 is equipped with a iioat controlled ballcock or valve 46, which maintains a constant water level and discharges the cold water into The numeral 46 designates a drain pipe having a vertical portion 41, passing through the bottom of the tank 42 'and having its upper intake end arranged near or at the water level. The vertical portion 41 is equipped with a thermostatically operated valve 48, arranged near the bottom of the tank 42. The valve 48 is closed as long as the water within the tank 42 is suliiciently cold to condense the steam within the coil 43 but when this water becomes too hot for this purpose, valve 48 automatically opens, draining the water from the tank 42 through the valve 48 and the vertical portion 41 beneath the valve 48. This will lower the level of the water within the tank 42, whereby ball-cock or valve`46 will open and cold water will be supplied in the tank 42, and when the temperature of the water within the tank 42 is again suitably lowered, valve 48 closes, and the level of the water within the tank 42 is restored. 'I'he pipe 24 is connected with the pipe 4I, as shown. A water jacket 49 may surround a portion of the vertical pipe 34, and this water jacket has upper and lower pipes D and 5I, leading into a hot water storage tank 52, as shown. The heat within the pipe 34 is therefore employed to heat the water within the tank 52.

At the forward end ofthe lower header I1 is a horizontal tube 53, extending to the exterior of the casing IIJ and leading into the header I1. This tube receives and has screw-threaded engagement, at 54, with a water spraying device or nozzle 55, having an adjustable needle valve 56, for controlling the neness of the spray. The nozzle 55 is preferably arranged concentrically of the header I1 and projects into its forward end. A pipe 51 is connected with the nozzle 55 and leads to the outlet side of a rotary pump 58,-the inlet side of which is connected with a pipe 59, which leads into the lower portion of the tank 42, below the water level. The pump 58 is driven by a motor 66.

The numeral 6| designates an oil burner, driven by a motor 62, and having a nozzle 63, discharging into the rebox or lower portion of the casing, in advance of the bridge I2, and the nozzle 63 extends through the opening I3. An electrically operated Stoker, or a gas burner may The pipe 33 has an adjustable backv pressure valve 35 connected therein. Inlet pipes be used, if desired, and I contemplate using any form of automatic heating device.

Disposed upon one side of the lower header I1 is a tubular housing 64, having its opposite ends closed. This tubular housing is in thermal contact with the header I1 and may be attached thereto by welding or the like. Arranged within the tubular housing 64 is a low temperature bulb 65, containing an expansible iluid. A pipe 66 is connected with the bulb 65 and passes to a pressure operated device 66. This pressure operated device includes a casing 61' and a flexible diaphragm 68', connected with a rod 69' and moved downwardly by a spring the tension of which may be adjusted. The numeral 61 designates a low temperature opening switch, including a blade 1 I to engage with terminals 12', connected in the wire 68. This wire is connected with one terminal of the pump motor 68, the other terminal of which is connected with a wire 69. When the lower header I1 is suitably heated so that it will instantaneously convert water sprayed therein into steam, the fluid within the bulb 65 is expanded, and will act upon the diaphragm B8', and shift the blade 1I into engagement with terminals 12, whereby the circuit is closed at the switch 61 and the pump motor 6I)l driven, provided the pump motorcircuit is closed at other points to meet the remaining conditions.

However, should the lower header I1 not be suiiiciently heated, then the action of the spring 10 would overcome the action ofthe :fluid within the bulb 65 upon the diaphragm 68' and blade 1I' would disengage terminals 12'. The switch 61 therefore opens upon the low temperature of the header I1. Disposed upon the opposite side of the header I1 is a horizontal tubular housing 13, having its opposite ends closed. This housing is in thermal contact with the header I1 and is Welded to the same. Arranged within the tu" bular housing 13 is a high temperature bulb 14, in thermal contact with the housing and containing an expansible fluid. The high temperature bulb is connected with a pipe 15 which leads to a pressure operated device 16' of a high temperature opening switch 16. The pressure operated device 16 includes a casing 11', having a flexible diaphragm 18' therein, which is moved downwardly by a spring 19'. The diaphragm 18 has connection with a rod 86', connected with a blade 8|', to engage terminals 82', connected with a wire 11a. One end of the wire 11a is connected with the wire/68 at 18, while its opposite end is connected with one terminal of the burner motor 62, the other terminal of which is connected with a wire 19, connected with the wire 69. The switch 16 is a high temperature opening switch and remains closed until the temperature of the header I1 reaches or exceeds the high danger point, at which time the iiuid within the tube 14 expands sufciently to overcome the action of the spring 19' and move lblade 8| out of engagement with terminals 82', whereby the switch 16 is opened and the burner motor 62 stopped.

The numeral 11 designates a high pressure opening switch, including a blade 11' to engage terminals 19', connected in wires 18a and 19a. The blade 11 is connected with a rod 19', secured to the iiexible diaphragm mounted in a casing 8 I This diaphragm 80' is moved downwardly by a spring 82', the tension of which may be adjusted. The pipe-30 leads into the casing 81'. The spring 82 normally holds the switch 11 closed, but when the pressure Within the upper header exceeds or reaches the high danger point,

this rpressure will raise the diaphragm 80' and shift blade 11' out of engagement with terminals 18', Wires 8i) and 8l are connected with a temperature control thermostatic switch 82, arranged in a room or the like. The wire 8I is connected with the wire 19, wire 18 is connected with Wire u8, and wire G9 is connected with wire 12, and Wire 80 is connected with wire 1 I.

The operation of the apparatus is as follows:

When the thermostat 82 calls for heat, it closes the circuit at that point. Since the pressure within the headers I1 and`25 is not now above or at the high danger point, the high pressure open ing switch 11 is closed, and since the header I1 is not now heated at or above a predetermined ternperature, the high temperature opening switch 16 is closed. Assuming that the header I1 has not as yet been heated to a suii'iciently high terne perature to instantaneously vaporize the water injected into the same, then the low temperature opening switch 61 is open. A circuit is therefore closed for driving the burner motor. In this closed circuit, current passes through wire 1I, wire 80, thermostat 82, wire BI, wire 19a, switch 11, wire 18a, wire 68, wire 11a, switoh 16, one terminal of motor 62, wire 19, wire 69 and back to the wire 12. The burner is therefore operated and the lower header I1 heated, but the p-ump motor 6I! has not been operated, since switch 61 was open. When the lower header I1 is heated suiiiciently for instantaneously vaporizing Ythe water sprayed therein, then the iiuid within the lower temperature bulb E will expand suiiiciently close the lower temperature opening switch S1 and a, circuit will be closed for driving the pump-motor GII. In this circuit, current will pass through wire 68, low temperature opening switch G1, one terminal of pump motor S0, and through the wire ES. When the pump motor is set into operation, the water will befed to the nozzle 55, which will continuously spray the same into the 'lower header I1. The iineness of the spray may be regulated by adjustment of fthe needle valve 'llhe burner motor E2 and the pump motor BI! are now both operating at the same time, since lower header is at or above the lower operating temperature `and below the high danger `tempeinture, any suitable number of degrees being allowed between these extremes. Should the temperature of the lower header I1 rise to or above the high danger point, the fluid within the high temperature bulb 1li will expand sufiiciently to open the high temperature opening switch 1li, thus stopping the operation of the burner motor 62, while the pump motor 6I) would continue to operate. Should the temperature of the header 1I: drop below the point for instantaneously vaporizing. water sprayed within the header, then the fluid within the low temperature bulb E5 would not be expanded suiciently to retain the low temperature switch S1 closed, v

and this switch would open, and the pump motor would stop, although the burner motor might be driving. As soon asV the action of the burner brings the header I 1 up to the selected high temperature to instantaneously vaporize the water, then the pump motor 6D is again set into action by he closing of the low temperature opening switch 51. It is thus seen that as long as the temperature of the header I1 is within selected limits that both motors 52 and SII may be operated, butt when this temperature reaches or exceeds the high danger point, the high temperature opening switch 16 will open and stop the motor 62 while the motor 60 continues to operate, and when the temperahire of the header I1 is below the point to instantaneously vaporize the water, the low temperature opening switch will open and stop the motor (it while the motor 52 continues to operate. However, should the pressure within the headers I1 and 25 rise to o1' above the danger point, then the high pressure opening switch 11 will open, and both motors 60 and 52 are stopped. The r'heosta 52 automatically closes and opens the circuit, stopping both motors @il and 52, if both are operating at that time, or stopping one motor if only one is operated.

Any water which may accumulate in the header I1 from condensation is fed to the trap 23 and returned by the pipe 24 to the pipe 4 I. As` soon as the water is sprayed into the header I1, it is converted into steam and passes upwardly into and through the tubes 21 to fthe upper header 25. The upper header and tubes serve as a 'superheater. The steam then passes through the pipe 3l, and lthrough the pipe 33 to the several radiators and is returned to the Vertical pipe 34. The returned steam enters the coil 43 and is condensed and discharged from the end 45 into the tank 42. rlhe pump 5.8 withdraws the water from the tank e2 and feeds it to the nozzle 55, The level of the water within the tank 4.2 is maintained constant by the action of the valve 46, and the temperature of the water is regulated by the valve e8. The back pressure valve 35 holds the pressure up to a predetermined point, when the unit is operated, and this back pressure valve opens when the pressure within the unit arises above the pressure necessary to open the switch 11. Ordinarily, the pressure will not get this high, as it would be limited b-y the opening of the switch 11. However, the opening of the back pressure valve under these conditions, would take care of an overriding pressure that might result from whatever additional expansion there might be from unevaporated water or saturated steam left in the retort i1 when the pressure switch 11 opens the circuit.

Instead of employing a rotary pump to feed the water to the nozzle 55, I may use a solenoid operated valve and supply the water to the valve under suitable pressure. The solenoid would be connected in the wire B8.

While I have shown a boiler unit including a single upper header and a single lower header, yet I may use a boiler unit having a plurality of upper headers and a plurality of lower headers. While I have shown only one boiler unit as a source of steam, yet I may employ any number of boiler units. While I have shown the boiler unit as supplying steam to radiators for heating purposes, yet the unit or units may be employed for supplying steam for any other purpose. In power applications, the temperature control 82 would be eliminated and the pressure limit switch 11 would be changed to one of the diierential type, having a low pressure cut in and a higher pressure cut out point. The setting of these points would be determined by the pressure desired for the system.

It is to be understood that the .form of my invention herewith shown and described is to be taken as a preferred example of the same, and that various changes in the shape, size, and arrangement of parts may be resorted to without departing from the spirit of my invention or the scope of the subjoined claims.

Having thus described my invention, what I claim is:

1. In a steam generator, a casing, a lower headerF withinthe casing, an upper header within the casing, 'tubes connecting the headers, a nozzle for supplying water into the lower header, means to supply water to the nozzle, means for controlling the operation of the water supply means and including a low temperature opening switch, pressure operated means connected with the switch, a bulb arranged within the casing adjacent to the lower header for holding an expansible uid and connected with the pressure operated means, a device for heating the lower header within the casing, means for operating the heating device, a high temperature opening switch for stopping the heating device operating means, pressure operated means connected with the high temperature opening switch, and a bulb arranged within the casing adjacent to the lower header for holding an expansible fluid and connected with the last named pressure operated means.

2. In a steam generator, a casing, a lower header'within the casing, an upper header within the Y casing, tubes connecting the headers, a nozzle for supplying water into the lower header, means for heating the lower header, means for supplying water to the nozzle and having its operation automatically stopped when the temperature of the lower header is reduced so that it will not substantially instantaneously vaporize the water and including a bulb arranged adjacent to the lower header, and means for automatically stop- 'ping the operation of the heating means when the temperature of the lower header reaches or passes a high danger point and including a bulb arranged adjacent to the lower header.

3. In a steam generatona casing, a lower header within the casing, an upper'header within the casing, tubes connecting the headers, a nozzle for supplying water into the lower header, means for heating the lower header, means for supplying water tothe nozzle and having its operation automatically stopped when the temperature of the lower header is reduced so that it will not substantially instantaneously'vaporize the water and including a. bulb arranged adjacent to the lower header, means for automatically stopping the operation of the heating means when the temperature of the lower header reaches or passes a high danger point and including a bulbarranged adjacent to the lower header, `and means for stopping the operation of the water supply means and the heating means when the pressure within the headers reaches or passes the high danger point.

4. In a steam generator, a casing, a lower header within the casing, an upper header within the casing, tubes connecting the headers, a nozzle for supplying Water into the lower header, means for heating the lower header, uneans for supplying water to the nozzle including an electrical device, a circuit connected with the electrical device, a switch biased to c-pen and connected in the circuit, a pressure operated device to close the switch and including a bulb arranged adjacent to the lower header, an electrical device to operate the heating means, a circuit connected with the lastnamed electrical device, a switch biased toclose and connected in the last-named circuit, anda pressure operated device to open the last-named switch and including a bulb arranged adjacent to the lower header.

5. In a steam generator, a casing, a lower header within the casing, an upper header within the casing, tubes connecting the headers, a nozzle for supplying water into the lower header, means for heating the lower header, means for supplying waterV to the nozzle including an electrical device,

a circuit connected with the electrical device, a switch biased to open and connected in the circuit, a pressure operated device to close the switch and including a bulb arranged adjacent to the lower header, an electrical device to operate the heating means, a circuit connected with the lastv'named electrical device, a switch biased to close and connected in the last-named circuit, a pressure operated device to open the last-named switch and including a bulb arranged adjacent to the lower header, a switch biased to close for controlling the supply of current to the clrcuits, and a pressure operated device to open the lastnamed switch and including a pipe in communication with the upper header.

6. In apparatus of the character described, a casing, a header within the casing, means to heat the header, a nozzle to supply water into the header, a condenser tank, a pump to withdraw water from the condenser tank and supply the same to the nozzle, means for receiving steam from the header, a Vreturn pipe connected with the discharge side of the means, a condenser coil within the tank below the water level thereof and discharging into the tank and connected with the return pipe, a water trap connected with the header and discharging into the condenser coil, float control means to supply cold water into the tank, and means to withdraw water from 'the tank when the temperature of the water rises to a selected degree.

7. In a steam generator, a casing, a boiler element arranged within the casing, a nozzle for spraying water into the boiler element, a device for heating the boiler element, means for supplying water to the nozzle and having its operation automatically stopped when the temperature vof the boiler element is reduced so that it will not substantially instantaneously vaporize the water, and means for operating the hea-ting device and having its'operation automatically stopped when the temperature of the boiler element reaches or passes a high danger point.

8. In a steam generator, a casing, a boiler element arrangedv within the casing, steam outlet means for the boiler element, a nozzle for spraying water into the boiler element, a device to supply water to the nozzle, a heating device for the boiler element, and means to cause the Water supply device and the heating device to operate at the same time, said means including a device to automatically stop the operation of the water supply device when the temperature of the boiler element is reduced so that it will not substan- 'v tially instantaneously vaporize the water, and a device to automatically stop the operation of the heating device when the temperature of the boiler element reaches or passes a danger point.

9. In a steam generator, a casing, a boiler element arranged within the casing, steam outlet means for the boiler element, a nozzle for spraying water into the boiler element, a device to supply water to the nozzle, a heating device for the boiler element, and means to cause the water supply device and the heating device to operate at the same time, said means including a pressure operated device to automatically stop the operation of the water supply device when the temperature of the boiler element is reduced so that it will not substantially simultaneously vaporize the water and including a bulb arranged adjacent to the boiler element, and a pressure operated device to automatically stop the operation of the heating device when the temperature of the boiler element reaches or passes a danger point and including a bulb arranged adjacent to the boiler element.

10. In a steam generator, a casing, a boiler ele ment arranged Within the casing, steam outlet means for the boiler element including a back pressure valve connected therein, a nozzle for spraying water into the boiler element, a device to supply water to the nozzle, a heating device for the boiler element, and means to cause the water supply device and the heating device to operate at the same time, said means including a pressure operated device to automatically stop the operation of the water supply device when the temperature of the boiler element is reduced so that it will not substantially simultaneously vaporize the water and including a bulb arranged adjacent to the boiler element, and a pressure operated device to automatically stop the operation of the heating device when the temperature of the boiler element reaches or passes the danger point and including a bulb arranged adjacent to the boiler element, and pressure operated means having communication With the interior of the boiler element to automatically stop both the Water supply device and the heating device when the pressure Within the boiler element reaches or passes the high danger point, the back pressure valve opening at a pressure above that necessary to operate the last-named pressure operated means. THAD C. JOHNSON. 

